TAZ Very loose Solid rod bearings?

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fillalph
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Re: TAZ Very loose Solid rod bearings?

Post by fillalph » Tue Jul 16, 2013 11:04 am

1013 wrote:I did replace the 3 in the X-carriage with ball bearings
Do you have a link to the part you used as a replacement?

1013
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Re: TAZ Very loose Solid rod bearings?

Post by 1013 » Tue Jul 16, 2013 5:06 pm

fillalph wrote:
1013 wrote:I did replace the 3 in the X-carriage with ball bearings
Do you have a link to the part you used as a replacement?
I used these from mcmaster carr. http://www.mcmaster.com/#standard-linea ... gs/=nnimgb
but at $20 each they are not cheap.

There are several seller of cheap ones out there. just search for LM10UU bearings. I ordered these: http://www.ebay.com/itm/12pcs-LM10UU-10 ... 19d90414ff for the machine I am building for home. $12.50 for 12 is super cheap...hopefully they are OK.

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Gemini64
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Location: Québec City, Canada

Re: TAZ Very loose Solid rod bearings?

Post by Gemini64 » Tue Jul 16, 2013 6:44 pm

Aren't those LM10UU bearings a lot noisier than the IGUS ones? I remember seeing a video comparison. Considering how much the IGUS sell, I'm guessing the Lulzbot guys went with them to reduce the noise.

Some people are also printing them in PLA with apparently good results.
1013 wrote:I have noticed some hysteresis in the Z-axis
Is there a link somewhere that explains what hysteresis is, in layman terms? I have no machine design background, and the Wikipedia page about it may as well be written in Mandarin. :oops:

jebba
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Re: TAZ Very loose Solid rod bearings?

Post by jebba » Wed Jul 17, 2013 5:35 am

Ya, we went with the igus LM10UU bushings primarily because of noise.

1013
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Re: TAZ Very loose Solid rod bearings?

Post by 1013 » Wed Jul 17, 2013 5:46 am

Gemini64 wrote:Aren't those LM10UU bearings a lot noisier than the IGUS ones? I remember seeing a video comparison. Considering how much the IGUS sell, I'm guessing the Lulzbot guys went with them to reduce the noise.

Some people are also printing them in PLA with apparently good results.
1013 wrote:I have noticed some hysteresis in the Z-axis
Is there a link somewhere that explains what hysteresis is, in layman terms? I have no machine design background, and the Wikipedia page about it may as well be written in Mandarin. :oops:

Hysteresis is the type of motion you get when you have backlash and friction.....basically, hysteresis is caused by a combination of backlash and other things, though backlash is usually the main cause.

lets say you command the X axis to move from 10mm to 100mm and you put an indicator on it and zero it out. Now you command the X axis to move to 190mm. and then you command it back to 100mm. The indicator will no longer be at exactly Zero, and the number you get (lets say you get 1mm) is the actual hysteresis. Backlash is one of the main causes of Hysteresis, but it is not the only one. Loose bearings, and high friction in the linear guides can also contribute to it.

another way to visualize hysterysis is to go out to your car, near the front wheel and push down on it to cmpress the spring and then slowly let it come back up. Measure the distance from the bottom of the car to the ground. Now pull up on the car and then slowly let it settle back down and re-measure. the difference in the measurement is the hysteresis.

Hysteresis is a general term that can apply to MANY things, not just mechanical systems. There is magnetic hysteresis, and electrical, as well as others I am sure.

1013
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Re: TAZ Very loose Solid rod bearings?

Post by 1013 » Wed Jul 17, 2013 5:49 am

jebba wrote:Ya, we went with the igus LM10UU bushings primarily because of noise.
there is more noise with the ball bearings, but I find the noise of the stepper motors to be louder...especially during rapid moves, so it seems to be a non-issue overall.

I hope lulzbot re-looks at the ball bearings, or at least gets some tighter IGUS style bearings in the future.

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Gemini64
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Re: TAZ Very loose Solid rod bearings?

Post by Gemini64 » Wed Jul 17, 2013 2:57 pm

Thanks for the hysteresis explanation!

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sox
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Re: TAZ Very loose Solid rod bearings?

Post by sox » Wed Jul 24, 2013 4:45 pm

I'm printing with a wrench on my bed to solve loose bearings on the y-axis. Adjusting them didn't help :/

cabbage_breath
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Re: TAZ Very loose Solid rod bearings?

Post by cabbage_breath » Fri Aug 30, 2013 1:37 pm

1013 wrote: There are several seller of cheap ones out there. just search for LM10UU bearings. I ordered these: http://www.ebay.com/itm/12pcs-LM10UU-10 ... 19d90414ff for the machine I am building for home. $12.50 for 12 is super cheap...hopefully they are OK.
Have you tested those cheap LM10UU bearings? I don't want to drop $50 on these bearings from the lulzbot store if I can pay $20 for something that works. Thanks.

JMILLER8731
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Re: TAZ Very loose Solid rod bearings?

Post by JMILLER8731 » Sun Sep 15, 2013 7:01 pm

McMastercarr sells ball bearing that work well for about 20$ a piece (xaxis you will need 3) they are a necessity if you are going to attempt dual extrusion

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